High temperature is a major threat to Pleurotus ostreatus cultivation. In this study, a potential mechanism by which P. ostreatus mycelia growth is inhibited under heat stress was explored. Lactate, as a microbial fermentation product, was found unexpectedly in the mycelia of P. ostreatus under heat stress, and the time-dependent accumulation and corresponding inhibitory effect of lactate on mycelial growth was further confirmed. The addition of a glycolysis inhibitor, 2-deoxy-d-glucose (2DG), reduced the lactate content in mycelia and slightly restored mycelial growth under high-temperature conditions, which indicated the accumulation of lactate can be inhibited by glycolysis inhibition. Further data revealed mitochondrial dysfunction under high-temperature conditions, with evidence of decreased oxygen consumption and adenosine triphosphate (ATP) synthesis and increased reactive oxygen species (ROS). The removal of ROS with ascorbic acid decreased the lactate content, and mycelial growth recovered to a certain extent, indicating lactate accumulation could be affected by the mitochondrial ROS. Moreover, metabolic data showed that glycolysis and the tricarboxylic acid cycle were enhanced. This study reported the accumulation of lactate in P. ostreatus mycelia under heat stress and the inhibitory effect of lactate on the growth of mycelia, which might provide further insights into the stress response mechanism of edible fungi.

高温是平菇栽培的主要威胁。在这项研究中，探索了在热应激下抑制P. ostreatus菌丝体生长的潜在机制。乳酸作为微生物发酵产物，在热应激下意外地发现在P. ostreatus的菌丝体中，并进一步证实了乳酸的时间依赖性积累和相应的抑制作用。加入糖酵解抑制剂2-脱氧-d-葡萄糖（2DG）在高温条件下降低了菌丝体中的乳酸含量，并略微恢复了菌丝生长，这表明糖酵解抑制作用可以抑制乳酸的积累。进一步的数据显示，在高温条件下线粒体功能障碍，有氧耗减少和三磷酸腺苷（ATP）合成减少以及活性氧（ROS）增加的证据。用抗坏血酸去除ROS可降低乳酸含量，菌丝体生长在一定程度上得以恢复，表明线粒体ROS可能影响乳酸的积累。此外，代谢数据显示糖酵解和三羧酸循环增强。这项研究报告了乳酸菌在平菇中的积累 热胁迫下的菌丝体和乳酸对菌丝体生长的抑制作用，这可能为食用菌的应激反应机理提供进一步的认识。